37 Left Anterior Choroidal Artery Infarction in Left Supraophthalmic Internal Carotid Artery Occlusion

Left Anterior Choroidal Artery Infarction in Left Supraophthalmic Internal Carotid Artery Occlusion

Clinical Presentation

A 29-year-old man complained of sudden onset of blurry vision which affected his left eye, worsened over a time period of 5 minutes, and then disappeared. In addition, he noticed painful eye movements predominantly on the left side. He had no vascular risk factors, but 5 months earlier he had been diagnosed with hepatitis C and was treated with ribarivin and peginterferon for 2 months. Neurologic examination revealed a right upper quadrant hemianopia. There were no other focal neurologic deficits. He was admitted under the initial differential diagnosis of a chronic inflammatory central nervous system (CNS) disease.

Initial Neuroradiologic Findings

Cranial CT on admission showed no abnormalities. Specifically, there were no signs of hemorrhage or territorial ischemia. Cerebrospinal fluid analysis on the following day revealed normal findings. Cerebral MRI on day 3 revealed hyperacute ischemia within the left anterior choroidal artery (AChA) territory and a single cortical lesion in the left parietal middle cerebral artery (MCA) territory on diffusion-weighted images but no signs of a chronic inflammatory CNS disease (Fig. B37.1). MR angiography (MRA) of the brain-supplying arteries was not performed.

Suspected Diagnosis

Left carotid artery pathology (stenosis or occlusion) or further proximal located embolic source

Questions to Answer by Ultrasound Techniques

Was there vessel pathology in the left extracranial common carotid artery (CCA) or internal carotid artery (ICA)?
Was there vessel pathology in the left intracranial ICA, in particular near the origin of the AChA (C2/C1-ICA)?
If a steno-occlusive ICA disorder was present, was there evidence of collateral blood flow via the anterior communicating artery (ACoA), posterior communicating artery (PCoA), ophthalmic artery (OA), or leptomeningeal vessels via the posterior cerebral artery (PCA)?

Neurosonologic Findings (Day 3)

Extracranial Duplex Sonography

B-mode ultrasound did not show atherosclerosis or other structural vessel abnormalities. Color-mode imaging was unremarkable. Doppler spectrum analysis revealed an increased pulsatility and reduced flow velocity in the left CCA in comparison with the contralateral side. The left ICA demonstrated markedly reduced caliber and flow velocities with increased pulsatility and a residual blood flow volume flow of 40 mL/min (Figs. B37.2–B37.7). Assessment of the vertebral arteries (VAs) was normal.

Transcranial Duplex Sonography

Nearly normal blood flow velocities and pulsatilities were seen in the M1-MCA and P1/P2-PCA of both sides. The A1 segment of the left anterior cerebral artery (ACA) demonstrated a retrograde flow but otherwise normal flow parameters. The right A1-ACA revealed a moderately increased flow velocity. A turbulent signal was seen in the ACoA, confirming the observed cross-flow. The left petrosal C6-ICA presented markedly reduced flow parameters, similar to the flow signals of the extracranial ICA. Normal findings were seen in the right C6-ICA and in both OAs (Fig. B37.8–Fig. B37.18).

Conclusion

Suspected left supraophthalmic ICA occlusion. Excellent collateral blood flow toward the left anterior circulation via ACoA and retrograde left A1-ACA.

Digital Subtraction Angiography (Day 5)

Selective digital subtraction angiography (DSA) was performed to evaluate the distal ICA pathology and to rule out near-occlusion. No pathology of the extracranial ICA was detected. Intracranially, a left-sided supraophthalmic ICA occlusion at the C1/C2-ICA level was confirmed. Furthermore, an undisturbed cross-flow was affirmed (Fig. B37.19).

Fig. B37.20 shows a schematic of the patient’s extra-and intracranial brain-supplying arteries.

Fig. B37.1(A) MRI diffusion-weighted image, axial plane demonstrating fresh infarction in the dorsal internal capsule and lateral geniculate body indicating partial AChA infarction (arrows). (B) MR T2-weighted image, axial plane, magnified view. Missing left ICA flow void (arrow) compared with the contralateral ICA and the basilar artery showing a normal flow pattern. (C) MRI diffusion-weighted image, axial plane, magnified view revealing also a small cortical parietal infarction in the left MCA territory (arrow).

Fig. B37.2 Extracranial duplex, longitudinal plane. Left CCA with normal flow velocity and mildly increased pulsatility (flow velocity 90/16 cm/s, PI = 1.8).

Fig. B37.3 Extracranial duplex, longitudinal plane. Left ICA revealing diminished caliber with reduced blood volume flow (BVF) and increased pulsatility (BVF 40 mL/min, PI = 1.4).

Fig. B37.4 Extracranial duplex, longitudinal plane. Left external carotid artery (ECA) with normal (noninternalized) flow signal (flow velocity 108/19 cm/s, PI = 1.8).